The present invention relates to a secretary telephone system for transferring a received call to a secretary or the like at a remote location so as to allow the secretary to handle the received call.
In general, the secretary telephone system is arranged as follows. As shown in the schematic system diagram of FIG. 1, when a call is received from a calling party telephone set A to a called party telephone set B, a telephone transfer unit 1 is operated to call a remote telephone set D through a local line of another telephone set C installed in the residence (i.e., subscriber residence) of the called party. When the secretary or the like anwsers the transferred call at the telephone D, the telephone set B is bidirectionally connected to the telephone set C by the telephone transfer unit 1. As a result, the calling party with the telephone set A can communicate with the secretary or the like with the telephone set D.
In a conventional secretary telephone system, when the telephone transfer unit 1 calls the telephone set D through the local line of the telephone set C and a busy tone is returned from the telephone station to the local line of the telephone set C because the line of the telephone set D is busy, the calling party will not hear the busy tone since the telephone set A is not connected to the telephone set B. The calling party receives only the ringing tones. Therefore, although the line of the telephone set D is busy, the calling party waits for a long period of time since he believes that he is calling the telephone set B or D, resulting in inconvenience.